The TLDR is that when you tell them you want to cancel, you have 60 days to do so and during that time you'll have no egress fees. Makes sense.
Biggest problem though is... if you have a substantial amount of data or need to do a complex and seamless transition - this probably won't work for you. I would have to be on the DevOps team that's told to move a complicated and data-heavy application, and they only had 60 days to do so. Also the bulk of the data movement is, in my experience, one of the first steps of migration - not the last.
My hope is that, if nothing else, this will spur similar behaviors in other large cloud providers ::cough::aws::cough::.